Symptomatic ring‐shaped medial meniscus

Evaluation of the morphological variations of the meniscus: a cadaver study

“…Watson–Jones [22] first reported on ring‐shaped meniscus in 1930. Since then, only few cases of ring‐shaped meniscus have been reported [2, 3, 8, 13, 15]. Most of them occurred in the lateral meniscus, and the actual prevalence is still unknown.…”

“…In some case reports, discoid medial meniscus [1, 6, 7, 18], ring‐shaped meniscus [2, 3, 8, 13, 15], and double‐layered meniscus [11, 17, 19, 20] have been reported as extremely rare cases. However, the accurate prevalence of these subtypes is still unknown.…”

Ressonância magnética na avaliação das variações anatômicas meniscais e da anatomia ligamentar perimeniscal: potenciais causas de erro de interpretação

“…Such variations are more prevalent in the population of Asian countries, in the lateral meniscus and are frequently asymptomatic (15) . Such variations include ring-shaped meniscus, both partial or complete meniscal hypoplasias, double-layer meniscus and meniscal insertion abnormalities (14,(16)(17)(18)(19)(20) .…”